1. Field of the Invention
The present invention relates to a scroll compressor suitable to a refrigerant compressor used for a refrigeration cycle for refrigeration and air conditioning or to a gas compressor for compressing gas such as the air and other gas.
2. Description of the Related Art
The scroll compressor is constructed by combining a stationary scroll and an orbiting scroll, and cast iron or aluminum alloy is generally employed as the material of a scroll member of the stationary scroll and the orbiting scroll. Further, there is also a combination of cast iron for the stationary scroll and aluminum alloy for the orbiting scroll.
Also, as described in Japanese Published Unexamined Patent Application No. H08-261172 and No. H08-261173, scroll members using two or more kinds of aluminum alloys are known.
In one described in Japanese Published Unexamined Patent Application No. H08-261172, the stationary scroll or the orbiting scroll is made a combination of two or more layers of aluminum alloys with the vicinity of the center part being constructed of a first material and with the vicinity of the outer peripheral part being constructed of a second material, and is formed by forging with two or more kinds of the aluminum alloys.
Also, Japanese Published Unexamined Patent Application No. H08-261173 describes one in which the stationary scroll or the orbiting scroll is made a combination of two or more layers of upper and lower faces of aluminum alloy materials and is formed by forging with two or more kinds of aluminum alloys.
In the prior art, when the scroll member is manufactured of cast iron, there is a problem that the centrifugal force increases in high speed rotation, and the load on bearings increases.
Also, when the scroll member is manufactured of an aluminum alloy, the weight can be reduced, however the thickness of the member is required to be made thick in order to suppress deformation of the member due to the load generated during the compression step of the scroll member. Therefore, there is a problem that the size of the member becomes large and the whole compressor becomes of a large scale. Further, when the material strength of the whole scroll member is to be increased to bear the load, there is a problem that the scroll member becomes expensive.
Also, as described in the Japanese Published Unexamined Patent Application No. H08-261172 and No. H08-261173, even those with the combination of two or more layers of two or more kinds of aluminum alloys have the difficulty in greatly increasing the rigidity of the scroll member and have the problem that the scroll member becomes expensive.